I've got high speed at work and at home. I love checking out videos of all kinds of cars. Usually every so often I'll go into the photos/videos section and go into a bunch of different topics that sound interesting and go on a downloading tear. Most other sites(notably the other major Protege site too btw) do not have subsections for every model to have it's own Photos and Videos.
I'd say the reasoning as well is that the majority of people on this site want to see an assortment of things when it comes to videos/photos. I don't just want to go to the Mazda3 video section, then the MSP then the MP3 etc....chances are I want to see videos of people drifting all types of cars, or doing quarter mile races etc. If I do get the urge to just look at one of them for some reason, then it's super easy to hit search, click on the Photos/Videos forum and type in "Mazdaspeed" or "drifting" or any other thing my heart desires and up will pop all the videos I'm looking for.
By this other proposed method, it might make it easier to find videos of specifically Mazdaspeed videos, but then it makes it very difficult to do searches for anything else that isn't specifically car related.
We already have around 30 or so forums and I think the breakdown is pretty good and this is more of an exercise in learning how to use the search feature if you are looking for something very specific.